Process of graphic reproduction



UNITED STATES PATENT OFFICE.

HENRI PERREGAUX, 0F LAUSANNE, SWITZERLAND;

PROCESS OF GRAPHIC REPRODUCTION.

No Drawing.

of printing ink which contains glycerin,; and the design can subsequently be removed from the plates by means of an acid so thoroughly that the plates are readily susceptible of re-use. The "metallic deposit in question is preferably obtained by moistening the plate and rubbing thereon a metal stylus which preferably consists of aluminium or an alloy of aluminium. If necessary, the relief may be accentuated by hollowing out the ground work by means of an acid which attacks glass.

To prepare a negative according to the process which formsthe subject of the. in-

vention, I may proceed for example, as fol- The edges of a smooth ground glass plate are chamfered, and after the surface of the plate has been moistened with water, the design to be reproduced is drawn thereu on by means of an aluminium stylus. Elie aluminium stylus leaves on the plate a mark which consists of a metallic deposit of aluminium adhering very strongly to the glass. The glass face in question is then dried, and inked by means of ordinary printing-ink containing, however, a certain proportion of glycerin, the introduction of this substance in the composition of the ink giving it a quality of not adhering to the glass but only to the metallic deposit which forms the design.

If it is desired to have the relief of greater height than that of the metal deposit, the ground work between the lines can be hollowed out by means of hydrofluoric acid, which attacks the glass wherever it contacts. This may be applied with a brush, or

Specification of Letters Patent.

Application filed April 22, 1920.

Patented Jan. 11, 1921.

Serial No. 375,819.

I may alternatively cover all the plate with a film of wax, and remove the wax Where desired and then expose the plate to the vapors of hydrofluoric acid.

The block or negative obtained by the process according to this invention is permanent, and can be made much cheaper than zinc blocks or blocks of composition obtained by the mechanical processes usually employed in reproducing a design which has first to be traced on paper. Manipula- I tion and electro-chemical baths are avoided, and as the original design is reproduced, the block follows faithfully the idea of the artist.

I Negatives or blocks thus obtained can be I used either for hand-printing by the aid of ink rollers or for machine-printingin ordinary presses. In the latter case, I may use either a number of relatively thin plates mounted upon a wooden stand with the interposition of a bedding of elastic material such as rubber, or I may directly employ glass blocks sufliciently thick to be gripped without other supports in the form of the press.

superposed and united by adhesives and can easily be made of such a thickness of glass as resists the usual pressures to which blocks are submitted in the big modern presses. The glass blocks may be adapted for re-use ,Ihese thick glass blocks may be i 7 formed integral'or may consist of plates by washingwith an acid, such as sulfuric or hydrofluoric, employing a suitable mop so as toerase the design. I find that it is possible to obtain reproductions on any paper so'iw'ell that the blocks can be used in combination with letter-press: and they can further be adapted for color reproduction according to the usual principles ofthe employment of polychrome blocks.

Claim.

The herein described process of graphic reproduction, consisting in-moistening a glass plate with water, drawing the design thereon by. means of an aluminum stylus, drying the glass plate, inking the design by means of a printing ink containing glycerin,

and utilizing the plate so prepared for print- 100 ing impressions of the inked design.

HENRI PERREGAUX. 

